The passive film on iron: an ellipsometric-spectroscopic study

Jovancicevic, Vladimir; Kainthla, R. C.; Tang, Zhongshu; Yang, Bo; Bockris, J. O'm.

doi:10.1021/la00075a020

Cited by 47 publications

(42 citation statements)

References 3 publications

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“…Similar O 1 s narrow scans have been reported in the XPS of oxidized iron, where the lower binding energy peak has been attributed to lattice oxygen (O 2‐ ) and the higher binding energy peak to chemisorbed OH ‐ groups, e.g. Fe–OH moieties . Given the small size of the Al signals in the unannealed Fe film, it seems likely that oxygen from Al 2 O 3 makes only a relatively small contribution to the O 1 s envelop, i.e.…”

Section: Resultssupporting

confidence: 63%

Multi‐instrument characterization of the surfaces and materials in microfabricated, carbon nanotube‐templated thin layer chromatography plates. An analogy to ‘The Blind Men and the Elephant’

Jensen

Kanyal

Madaan

et al. 2013

Surface & Interface Analysis

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We apply a suite of analytical tools to characterize materials created in the production of microfabricated thin layer chromatography plates. Techniques used include X-ray photoelectron spectroscopy (XPS), valence band spectroscopy, time-of-flight secondary ion mass spectrometry (ToF-SIMS) in both positive and negative ion modes, Rutherford backscattering spectroscopy (RBS), and helium ion microscopy. Materials characterized include: the Si(100) substrate with native oxide: Si/SiO 2 , alumina (35 nm) deposited as a diffusion barrier on the Si/SiO 2 : Si/SiO 2 /Al 2 O 3 , iron (6 nm) thermally evaporated on the Al 2 O 3 : Si/SiO 2 /Al 2 O 3 /Fe, the iron film annealed in H 2 to make Fe catalyst nanoparticles: Si/SiO 2 /Al 2 O 3 /Fe(NP), and carbon nanotubes (CNTs) grown from the Fe nanoparticles: Si/SiO 2 /Al 2 O 3 /Fe(NP)/CNT. The Fe films and nanoparticles appear in an oxidized state. Some of the analyses of the CNTs/CNT forests appear to be unique: (i) the CNT forest appears to exhibit an interesting 'channeling' phenomenon by RBS, (ii) we observe an odd-even effect in the SIMS spectra of C n -species for n = 1 -6, with the n ≥ 6 ions showing a steady decrease in intensity, and (iii) valence band characterization of CNTs using X-radiation is reported. Initial analysis of the CNT forest by XPS shows that it is 100 at.% carbon. After one year, only ca. 0.25 at.% oxygen is observed. The information obtained from the combination of the different analytical tools provides a more complete understanding of our materials than a single technique, which is analogous to the story of 'The Blind Men and the Elephant'. The raw XPS and ToF-SIMS spectra from this study will be submitted to Surface Science Spectra for archiving.

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Section: Resultssupporting

confidence: 63%

Multi‐instrument characterization of the surfaces and materials in microfabricated, carbon nanotube‐templated thin layer chromatography plates. An analogy to ‘The Blind Men and the Elephant’

Jensen

Kanyal

Madaan

et al. 2013

Surface & Interface Analysis

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“…There is an inner, adherent and coherent layer with a spinel structure, consisting of Fe 3 [ [19][20][21] Various proposals have been made for the composition and structure of the outer layer in the passive region, namely Fe(OH) 2 , [17,22] a hydrated FeOOH (a-, b-, dand g-forms), [9,21] g-FeOOH, [12,23] a hydrated amorphous or polymeric oxide. [5,11,12,[24][25][26] In a recent study of the growth of the passive film on iron in 0.05 M NaOH using Raman microscopy in situ with preresonance enhancement during successive cycles of anodic and cathodic polarisation, [27] the iron oxides and oxyhydroxides present on the surface in the passive region were determined to be largely g-Fe 2 O 3 , a-FeOOH, d-FeOOH, g-FeOOH and Fe(OH) 2 . The relative amounts of these compounds were found to vary with potential within the passive region and also with different cycles.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the composition of the passive film on iron under pitting conditions in 0.05 M NaOH/NaCl using Raman microscopy in situ with anodic polarisation and MCR‐ALS

Nieuwoudt

Comins

Cukrowski

2011

J Raman Spectroscopy

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The composition of the surface film formed on pure iron was investigated in a solution of 0.05 M NaOH and 0.05 M NaCl. Raman spectra of the film were recorded in situ during anodic polarisation over the passive region after addition of the NaCl to the electrolyte, under conditions of preresonance enhancement using excitation at 636.4 nm. Multivariate curve resolution with alternating least squares analysis was applied to the spectra to measure the relative amounts of different iron oxide and oxyhydroxides in the film at different potentials. The water content was also determined in this way from Raman spectra recorded using excitation at 514.5 nm. It was found that the composition of the film and the amount of incorporated water were influenced by the applied anodic potential. The results show that stable pitting can occur when the composition changes from the primary constituents β-FeOOH and Green Complex (a hydrated, amorphous magnetite) with smaller amounts of γ-Fe 2 O 3 and γ-FeOOH, to δ-FeOOH and Green Complex, simultaneously with a reduction in water content. These changes result in conditions that favour the rate of localised breakdown of the film by Cl − ions over the rate of repassivation by water in the passive film.

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“…The purpose of the present work is to demonstrate the formation of soluble species during the anodisation of Fe in K2CO3-KHCO 3 solutions through the use of Manuscript received 15 November 1989. the rotating ring disc electrode technique and to provide information about the composition of the passivating surface layer through XPS analysis. [27][28][29] EXPERIMENTAL METHOD The experimental arrangement was the same as described elsewhere. 23 '24 The formation of soluble iron species during the voltammetric sweep of Fe electrodes immersed in carbonate-bicarbonatecontaining solutions was followed through a rotating ring-disc electrode (RRDE).…”

Section: Introductionmentioning

confidence: 99%

Iron dissolution and passivation in K2CO3-KHCO3 solutions. rotating ring disc electrode and XPS studies

Castro¹,

Vilche²,

Arvía³

1991

Corrosion Science

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Rotating ring-disc electrode studies on the anodic dissolution and passivation of iron in potassium carbonate/bicarbonate buffers at 25°C show that in the active anodic dissolution potential range Fe(II) soluble species are generated. This reaction is favoured by the presence of bicarbonate ions in solution and it is explained through the formation of an unstable soluble complex containing Fe(lI) and HCO3 ions. This suggests that the anodic layer at a certain stage of its formation contains some amount of carbonate species. XPS data of surface layers produced at different anodic potentials confirm the presence of the carbonate species in thick anodic layers grown in the prepassive potential region in still solutions, whereas the opposite result is found for the thin passive layers formed at high positive potentials.

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The passive film on iron: an ellipsometric-spectroscopic study

Cited by 47 publications

References 3 publications

Multi‐instrument characterization of the surfaces and materials in microfabricated, carbon nanotube‐templated thin layer chromatography plates. An analogy to ‘The Blind Men and the Elephant’

Multi‐instrument characterization of the surfaces and materials in microfabricated, carbon nanotube‐templated thin layer chromatography plates. An analogy to ‘The Blind Men and the Elephant’

Analysis of the composition of the passive film on iron under pitting conditions in 0.05 M NaOH/NaCl using Raman microscopy in situ with anodic polarisation and MCR‐ALS

Iron dissolution and passivation in K2CO3-KHCO3 solutions. rotating ring disc electrode and XPS studies

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